This invention relates to aircrew ejection seats in general and more particularly to inflatable devices for securing the aircrew member safely in his seat during ejection.
Of major concern when a fighter aircraft is disabled in the air, is ejecting the crewmembers safely. In fighter aircraft, the air crewmembers initiate the process of ejection by pulling on an ejection handle, squeezing an ejection handle or some similar device to initiate ejection. The canopy that encloses the air crewmembers inside the aircraft cockpit is first blown or cut away. Next, the seat ejects out of the aircraft by a ballistic catapult along guide rails and the seat and air crewmember sitting thereon begins to enter the windblast. After the seat separates from the guide rails, it is propelled clear of the aircraft by rocket motors. When the seat reaches a safe trajectory, a parachute deploys for returning the air crewmember to the earth. The seat is stripped from the aircrew member and falls back to earth.
The proper positioning of the aircrew member in his seat is necessary for a safe ejection from the aircraft. Such a positioning requires that the aircrew member is correctly aligned in his seat and that his arms and legs are safety stowed. Many factors affect positioning such as the altitude and attitude of the aircraft, is it flying straight, level and upright or is it in some other position?
A system identified as Inflatable Body and Head Restraint System; xe2x80x9cIBAHRSxe2x80x9d has been proposed which provides a pair of inflatables inside the vertical harness that extends from the five point rotary buckle to each shoulder. IBAHRS is a passive system that automatically tightens the harness at the onset of the ejection. The inflatable pretensions the straps and forces the occupant back against the seat. This action lessens the chances of the aircrew member from striking cockpit objects during the emergency.
However in fixed wing aircraft, there is a system that uses a net-like device that comes out from the seat to keep the arms and maybe the legs close to the body. In this way, when the aircrew member clears the aircraft, the air blast or windblast will not cause his limbs to flail. Around the ankles of the aircrew member are xe2x80x9cgarter-likexe2x80x9d restraints that tethered to the seat. During normal flying, the aircrew member""s legs are free to move around, but during ejection, the tethers are pulled tight pulling the legs against the seat. Later when the aircrew member is ready to leave the seat, the tethers are cut and the legs are no longer secured to the seat.
The location of the ejection handle if is between the aircrew member""s legs, is designed so that as the aircrew member pulls the handle, this forces his arms up and in toward the center of his body. When the ejection handles are on the arm rests; the squeezing of the handles tends to keep the aircrew member""s arms in position along his body.
U.S. Pat. No. 4,508,294 issued to Lorch on Apr. 2, 1985 and entitled xe2x80x9cAir Bag Restraint Systemxe2x80x9d teaches an air bag member which is deployed from a stored position frontally to the chest of the aircrew member. The air bag member is guided upward and downward along tracks on either side of the seat so that the upper body of the aircrew member is enclosed within the seat just before ejection. In this patent, it is mention that windblasts are up to 1600 pounds per square foot, about 11 pounds per square inch. This force greets the aircrew member as he clears the aircraft.
U.S. Pat. No. 4,436,262 describes a windblast head protector for use during the aircrew""s ejection from the aircraft. U.S. Pat. No. 4,465,250 describes a flight suit that has means on the suit into which the aircrew member snaps a hook. The hook and flight suit means function to restrain the legs against the seat during ejection.
It is a principal advantage of the present invention to position an aircrew member in his ejection seat before the ejection seat starts moving out of the aircraft.
It is yet another advantage of the present invention to ensure that an aircrew member is securely position during ejection to avoid or reduce injury to the crewmember.
It is yet another advantage of the present invention to provide inflatables in an ejection seat that are inflated in concert with the start of the ejection sequence to center the aircrew member in the ejection seat and maintaining the proper center of gravity of the seat.
It is still another advantage of the present invention to provide spine and body stiffening to the aircrew member by inflatables stowed in the ejection seat.
These and other advantages are found in an inflatable restraint system for protecting an aircrew member during ejection having a central L-shaped tubular member with the vertical arm of the xe2x80x9cLxe2x80x9d extending from the ankles. The vertical arm extends in front of the legs to above the knees and the horizontal arm of the xe2x80x9cLxe2x80x9d extends toward the chest of the aircrew member. At least one pair of tubular members extends from either side of the central tubular member and extends along the aircraft seat. The pair of tubular members is in fluid communication with the central tubular member.
A tubular manifold member is secured to the vertical arm of the xe2x80x9cLxe2x80x9d shaped central tubular member and is positioned between the ankles and the knees of the aircrew member. The manifold member is positioned between the central tubular member and the aircraft seat and is in fluid communication with the central tubular member. The manifold member has an inflation inlet.
A sheet member is connected to the central tubular member and the pair of tubular members. The sheet member is connected to the least one pair of tubular members and is operable to enclose the arms and the legs of the aircrew member before entering the windblast during ejection. A source of inflating fluid connected to the inflation inlet and is operable upon command to inflate the tubular members and with the sheet member pulled taut, to form a shield around the aircrew member in the aircraft seat.